Cast Slip with Preset Carbide Buttons

ABSTRACT

A slip for support of a downhole tool is cast with inserts positioned in the mold. The inserts can have a unique shape to allow them to be retained in the cast slip while having the proper position relative to each other and proper extension and orientation. A placement tool is envisioned to allow sets of inserts to be initially placed in the mold at one time and released from the tool.

FIELD OF THE INVENTION

The field of this invention is gripping members for downhole tools and more particularly techniques for manufacturing slips that have inserts in their grip faces.

BACKGROUND OF THE INVENTION

Gripping members for downhole tools such as packers have had hardened inserts in them to enhance grip. The most common way of building such parts is to fabricate the slip shape and then machine holes in the manufactured shape. The inserts then are placed by hand in each opening and secured to the opening usually by a welding technique. Some examples of this technique can be seen in U.S. Pat. Nos. 4,212,352; 6,899,183; 6,793,022 (FIGS. 11-13); 6,481,497 (FIG. 3C); 6,164,377, 6,378,606 and 5,984,007.

The problem with this technique is that it is expensive due to the significant amount of hand labor and machining involved in precisely locating the blind bores or through bores in small slips and then properly fixating the insert in the intended location while fixating it. This is further made more difficult by the small size of the slip body and the close quarters mounting of the inserts on the small body.

The present invention is a technique for producing such slips more economically by assembling the inserts into a mold and casting the slip with the inserts already in place and properly positioned. The inserts can have unique shape to help retain them in position during use. To further expedite the process, a fixture can be used to retain all the inserts for a particular slip and allow them all to be inserted in a proper placement in the mold. These and other aspects of the present invention will be more readily apparent to those skilled in the art from a review of the detailed description and the associated drawings while recognizing that the claims present the full scope of the invention.

SUMMARY OF THE INVENTION

A slip for support of a downhole tool is cast with inserts positioned in the mold. The inserts can have a unique shape to allow them to be retained in the cast slip while having the proper position relative to each other and proper extension and orientation. A placement tool is envisioned to allow sets of inserts to be initially placed in the mold at one time and released from the tool.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a section view in a mold showing the inserts uniquely configured to be retained in position after the pour; and

FIG. 2 is a schematic illustration of the tool to allow placement of a set of inserts into a mold at the same time.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

FIG. 1 illustrates a two piece mold 10 and 12 where the lower piece 12 has openings 14 to accept inserts such as 16 in a specific orientation. Inserts 16 are preferably made of tungsten carbide however other hard materials previously used for inserts could also be used. Symbolically represented is a way to support the inserts with respect to the mold lower 12 is a support 18 so that the desired amount of extension of insert 16 is obtained before the pour through inlet 20. Another way to get proper extension and orientation is to size openings 14 such that friction or an interference fit holds the inserts 16 in the proper extension and orientation until the pour. Alternatively, an internal support 20 can hold each insert 16 at the proper offset from the bottom 24 of the mold lower portion 12. In the preferred embodiment, the inserts 16 can have an irregular shape such as a larger head 26 that when spaced from the bottom 24 before the pour will result in the slip being formed all around the head 26 and a portion of the shank 28 to better fixate the insert 16. Other irregular shapes that aid in insert 16 retention are contemplated.

FIG. 2 illustrates a tool 30 with a handle 32 that can grip a plurality of inserts 16 and selectively release them with a quick release feature 34 after the insertion into position as shown in FIG. 1. The tool can be manually operated or manipulated robotically as part of a mass production assembly when a belt (not shown) brings the mold lower 12 into alignment with the tool 30. Continuing the concept of automation, the mold upper 10 can be joined to the mold lower 12 by another robot and the pour then follows. The loading of inserts 16 into tools 30 can be done manually or alternatively that process can also be automated. This would involve getting the individual inserts 16 into the proper orientation and grid pattern and engaging the array to a tool 30 that can then be robotically moved to engage a mold lower 12.

Welding brazing or adhesives do not need to be used in the method. Various arrays of slips can be used. Arrays with slips oriented to grip against forces in opposed direction are contemplated. Mirror image arrays are possible.

The above description is illustrative of the preferred embodiment and many modifications may be made by those skilled in the art without departing from the invention whose scope is to be determined from the literal and equivalent scope of the claims below. 

1. A method of producing a slip with at least one insert for downhole use, comprising: providing a mold having at least one opening; placing an insert in said opening so that at least a portion thereof extends outside said mold; adding material for the slip into said mold to fixate said insert.
 2. The method of claim 1, comprising: supporting said insert from outside said mold as it extends through said opening.
 3. The method of claim 1, comprising: supporting said insert from inside said mold as it extends through said opening.
 4. The method of claim 1, comprising: supporting said insert from said opening as it extends through said opening.
 5. The method of claim 4, comprising: using an interference fit between said insert and said opening to support said insert during said adding material.
 6. The method of claim 1, comprising: providing an irregular shape on a portion of said insert disposed in said mold.
 7. The method of claim 1, comprising: providing a plurality of openings in said mold; inserting a plurality of inserts into said openings at one time.
 8. The method of claim 7, comprising: securing a plurality of inserts to a rack; using said rack to install said inserts together.
 9. The method of claim 8, comprising: releasably mounting said inserts to said rack; releasing said inserts from said rack after installing them in said openings.
 10. The method of claim 1, comprising: securing the insert to the slip without welding or brazing.
 11. The method of claim 1, comprising: forming said insert into a t-shape having a transverse member and a shank; extending said shank through said opening with said transverse member in said mold.
 12. The method of claim 1, comprising: providing a plurality of openings in said mold; inserting the portion of said inserts that extend beyond said openings in a mirror image orientation. 